The invention concerns the rotors of axial turbine engines of the type comprising a disk or a drum having a rim equipped with a plurality of longitudinal, profiled grooves wherein the roots of the rotor blades of the turbine engine are engaged. The roots of the blades of the turbine engines of this type are secured by annular flanges, whereby they are prevented from leaving by way of the ends of the grooves. The invention concerns more precisely the flanges mentioned above and applies specifically to the downstream flange of a gas turbine with a rotor cooled by means of air circulation.
The cooling air, generally taken from the air flow delivered by the compressor for a group of gas turbines, is conducted into feed cavities provided in the turbine disk, then traverses cooling canals of the blades, together with spaces bounded on the outside by the platforms for the blades and internally by the apexes of the teeth of the disk, between the grooves. The cavities and the spaces are normally supplied with air from upstream and therefore leaks in the downstream direction must be prevented. In addition to securing the roots of the blades, the downstream flange must thus insure the air tightness of the feed cavities and the spaces in the downstream direction. The flange also serves as a thermal shield. The flanges must be as light as possible so that they will not generate excessive centrifugal stresses in the disk. Furthermore, they must not generate local stresses in the disk or the blades. This consideration leads to the elimination of the fastening of the flanges by means of bolts, because the holes necessary for the passage of the bolts are locations of stress concentrations; also, such bolts and nuts would form a relief pattern on the surface of the rotating disk, which through friction with the ambient air, would produce heating harmful to the mechanical strength of the rotor.